PURPOSE: To provide a pyridopyridazine derivative which is a chemoluminescent substance useful for the analysis utilizing chemoluminescence.
CONSTITUTION: A compound of formula I [R1 is (substituted)hydrocarbon group or (substituted)heterocyclic group; R2 is OH, SH, amino or monosubstituted amino; when R3 is monosubstituted amino, R3 and R1 may together form a ring; R3 is H, (substituted),QH, (substituted)amino, (substituted)SH, halogen, heterocyclic group, NO2, CN, (esterified or amidated) carboxyl, azido, sulfo or organic sulfonyl; R3 is not H when R1 is aliphatic group; X is 0 or S] or its salt, e.g. 8-hydroxy-7-(p-methoxyphenyl) pyrido[3,4-d]pyridazine-1,4(2H,3H) dione. The compounds of formula are new except for those wherein R3 is H and R1 is (substituted)aralkyl or unsubstituted aryl. For example, a compound of formula II (R is lower alkyl) is made to react with hydrazine to obtain the corresponding compound of formula I wherein X is O.
ARAMAKI YOSHIO
KONDO KOICHI
